1. Field
The present invention relates to control systems, and in particular, but not by way of limitation, the present invention relates to systems and methods for managing and maintaining mass flow controllers.
2. Background
For many manufacturing processes (e.g., thin film deposition processes), it is very important that the mass flow rates of process fluids that are fed into a process chamber be precisely controlled. But many issues arise during ongoing operation of mass flow controllers that adversely affect the ability of mass flow controllers to accurately control mass flow rates.
From the perspective of the user/operator, the particular issues that arise are often not readily apparent or are unexpected, which leads to a high cost of ownership due to unscheduled maintenance. For example, the issues (e.g., minor operating inaccuracies to complete failures) may occur without any immediate indication as to what caused the specific type of undesirable operation. Moreover, users often lack the training, tools, and/or desire to diagnose issues; thus users of mass flow controllers may simply replace mass flow controllers when issues arise. As a consequence, mass flow controllers are often replaced when information about the underlying problem could lead to a simple remedy.
To diagnose issues with a mass flow controller before any major problems occur, the mass flow controller may be removed from the tool (e.g., a plasma processing system) and run through a series of tests under controlled conditions (e.g., at a separate test location). This approach, however, requires the tool to be taken offline, which is a time consuming and potentially very costly approach to diagnosing potential problems with a mass flow controller. Accordingly, a need exists for mass flow controller diagnostic methodologies that are simpler and more cost effective.